Such an intake module usually has a housing which is fitted with an inlet opening for fresh air and with a flange section for fastening or connecting the housing to the internal combustion engine. A plurality of outlet openings for fresh air are provided in the flange section. A distributor chamber is usually formed in the housing, from which the fresh air supplied via the inlet opening is distributed to the outlet openings during operation of the internal combustion engine. In this case, at least one such outlet opening is provided per combustion chamber of the internal combustion engine. Such an intake module can be used both with a charged internal combustion engine and also with a non-charged internal combustion engine.
It is also usual to fit such intake modules with a control device for controlling a cross-section of at least one of the outlet openings through which flow can take place. Usually at least one such controllable outlet opening is assigned to each combustion chamber. It can further be provided that two outlet openings are assigned to each combustion chamber of the internal combustion engine, of which respectively one is controlled, i.e. can be varied in relation to its cross-section through which flow can take place whilst respectively the other is non-controlled, i.e. is permanently completely open. With the aid of such a control device, the fresh air supply can be optimized depending on the current operating state of the internal combustion engine. Such a control device can be provided with a control shaft which has at least one control valve arranged in a rotationally fixed manner on the control shaft for the respective outlet opening. With the aid of the respective control valve, the respective outlet opening can thus be controlled with respect to the cross-section through which flow can take place. In particular, the respective outlet opening can be opened or closed with the aid of the appurtenant control valve. Arbitrary intermediate positions are fundamentally also feasible. Depending on the function of the control valve, this can also be designated as a tumble valve or swirl flap.
Since such an intake module should be produced in large numbers and as cheaply as possible, additional problems are obtained with the mounting of the control shaft on the housing. The housing which is usually injection-moulded from plastic can be distorted due to production which can adversely affect mounting of the control shaft with the lowest possible friction. As a result however there is the risk of the functional reliability of the control shaft being adversely affected. Accordingly, the expenditure for achieving a functionally reliably mounting of the control shaft on the housing is comparatively high. Additional problems can arise, for example, during subsequent installation of the control shaft in the housing if the installation should be carried out, for example, on a connection side of the flange section provided for connection of the housing to the internal combustion engine. Warpage of the housing results in relatively high manufacturing tolerances which make functionally reliable assembly of the control shaft difficult.
These problems not only occur in intake modules with controllable outlet openings but in all intake modules in or on the housing of which controllable openings are provided. Accordingly, the present invention is not restricted to intake modules with controllable outlet openings but relates to all intake modules which have or contain controllable openings. Thus, it also relates to intake modules which have bypass openings in the interior thereof, which can be opened and closed for switching intake tube lengths. To this end, such a control device can also be used to control the cross-sections of these bypass openings through which flow can take place.
Known from DE 44 99 626 T1 is an intake module for a fresh air system of an internal combustion engine which is provided with a housing which has an inlet opening for fresh air and a flange section with a plurality of outlet openings for fresh air. The known intake module has switchable intake tube lengths whose effective length is switched by opening and closing bypass openings. To this end, the intake module is also fitted with a control device for controlling a cross-section of these bypass openings through which flow can take place. The control device comprises a control shaft and a plurality of control valves for the bypass openings arranged in a rotationally fixed manner on the control shaft. The control shaft is rotationally mounted about an axis of rotation on the housing by means of at least one bearing bracket. The housing has at least one bearing receiving portion for receiving the respective bearing bracket which has an insertion opening. In this case, the respective bearing bracket is inserted in an insertion direction oriented perpendicularly to the axis of rotation through the respective insertion opening into the appurtenant bearing receiving portion. The respective bearing bracket has two bearing parts, namely a first bearing part and a second bearing part. The two bearing parts each have an inner surface which face one another in relation to a transverse direction oriented perpendicular to the axis of rotation and perpendicular to the insertion direction which extend perpendicularly to the transverse direction and which abut against one another in a flat manner. In the known intake module the bearing parts each have a bearing region. The two bearing regions are configured so that a linear and radially pre-stressed contact to the control shaft is obtained at a plurality of points distributed in the circumferential direction.